This is good for me to know, actually. What operating system are you running on?

My advice would be to wait until I get the problem figured out, unfortunately. The lighting code does work fine on Windows, however it may have problems on linux, which is weird because the code uses OpenGL and was originally developed on linux.

3) The lighting code uses some fairly basic OGL features and doesn't use any extensions, which is why I'm having trouble thinking of what is going wrong. However, I'd recommend concentrating on the lighttest.d file and tweaking OpenGL parameters there to see if you get any interesting results.

One is important: set filtering to linear for the penumbrae (filtering defaults to nearest_mipmap_nearest which I think is a bit unexpected).

The others are not that important. I replaced light.png with a physically correct attenuation (1/(1 + d^2)). Of course now the lights have infinite range which may be a bit of a problem but looks alright. I also replaced penumbra.png with a physically more correct version. Instead of a linear gradient it is based on how much of a circle would be visible, so it is an approximation of spherical lights while the linear gradient (at least I think it was linear) was an approximation of cylindrical lights.

I like how it looks now and feel inspired to create a game that uses it heavily .